A waste magnet regeneration method includes the following steps. First, waste magnets and auxiliary alloys are provided, pre-treat the waste magnets, hydrogen decrepitating and sieving the waste magnets and the auxiliary alloys to form main alloy powders and auxiliary alloy powders. The main alloy powders and the auxiliary alloy powders are mixed in a predetermined ratio to form a mixture, and then the mixture is subjected to the jet mill pulverization, magnetic field alignment compacting, sintering and aging treatment to obtain a regenerated magnet.

Disclosed are a cerium magnet with diffused grain boundaries containing REFe2 and a preparation method therefor, wherein an original cerium magnet contains a 2-14-1 main phase, a REFe2 phase and a rare earth-rich phase, and the REFe 2 phase is a CeFe2 phase or a (Ce,RE′)Fe2 phase. The RE″ element in a rare earth diffusion source is diffused into the original cerium magnet by means of a grain boundary diffusion treatment at the melting point of the REFe2 phase, and same is then cooled directly or cooled after a tempering treatment to room temperature to obtain a final cerium magnet. The final cerium magnet contains a new 2-14-1 main phase, a new enhanced REFe2 phase and a new rare earth-rich phase, wherein the new 2-14-1 main phase is a (Ce,RE″)2Fe14B or (Ce,RE′,RE″)2Fe14B main phase, and the new enhanced REFe2 phase is a (CeRE″)Fe2 phase or a (Ce,RE′,RE″)Fe2 phase, wherein RE′ and RE″ are one or more of La, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. The cerium magnet improves the diffusion efficiency of the element RE″ in the diffusion source, and substantially improve the coercivity thereof.

The present invention relates to an alloy with formula of RE-M-B—Fe as defined herein and oxygen content less than 0.9 wt %, wherein said RE is in the range of 29.0 weight % to 33.0 weight %; M is in the range of 0.25 weight % to 1.0 weight %; B is in the range of 0.8 weight % to 1.1 weight %; and Fe makes up the balance. The present invention also relates to a method for preparing a RE-M-Fe—B magnetic powder, as defined herein comprising the steps of: (a) melt spinning a RE-M-Fe—B alloy composition to obtain a melt-spun powder; (b) pressing the melt-spun powder of step (a) to obtain a compact body; (c) hot deforming the compact body of step (b) to obtain a die-upset magnet; (d) crushing the die-upset magnet of step (c) to obtain a powder; (e) milling and sieving the powder of step (d); and (f) passivating the powder of step (e) to obtain a magnetic powder; wherein: each of steps (d) to (f) is performed under a low oxygen environment and transfer between each of steps (d) to (f) is a sealed transfer; and wherein the oxygen content of the low oxygen environment and during each sealed transfer is below 0.5 weight %.

A dual-rotor machine comprising a dual rotor support structure rotatably connected to a frame. A stationary stator is disposed between the rotors and is fixed to the frame. An inner rotor and outer rotor, each comprising a permanent magnet Halbach array, are coaxially disposed with the stator and are rotable about the stator. In this configuration, the inner rotor channels its magnetic flux to its outside, while the outer rotor channels its magnetic flux to its inside. The magnetic flux density at the stator for the dual-rotor machine can be as high as 2 Tesla or higher for high-grade neodymium-iron-boron permanent magnet material, and the stored magnetic energy for conversion to mechanical or electrical energy available to the stator may be at least 0.5 kJ/m. The rotor Halbach arrays may comprise monolithic permanent magnets with continuously variable magnetic field direction.

The present invention provides a manufacturing method for obtaining a compression-bonded magnet with which it is possible to achieve, at a high level, both a residual magnetic flux density (Br) and the magnitude of a reverse magnetic field (Hk) that reduces Br by 10%. The manufacturing method of the present invention includes a molding step of compressing a bonded magnet raw material composed of a compound or the like of magnetic powder and a binder resin in a heated and oriented magnetic field. The bonded magnet raw material has a mass ratio of the magnet powder of 90 to 95.7 mass% to a total of the magnet powder and the binder resin. The magnet powder includes coarse powder having an average particle diameter of 40 to 200 .Math.m and fine powder having an average particle diameter of 1 to 10 .Math.m. The coarse powder has a mass ratio of 60 to 90 mass% to a total of the coarse powder and the fine powder. The coarse powder includes rare earth anisotropic magnet powder subjected to hydrogen treatment. The binder resin includes a thermosetting resin. The molding step is carried out with a compressing force of 8 to 70 MPa and a heating temperature of 120° C. to 200° C.

A rare-earth magnet according to an embodiment of the present invention comprises: a rare-earth magnet precursor including a composition of (R1(1-x)R2x)yFe(100-y-z-v-w)CozBvTMlw in which R1 comprises at least one of Nd or Pr, and R2 comprises Ce; and a diffusion metal including a composition of (LRE(100-p-q)HREp)TM2q, and diffused on the surface of the rare-earth magnet precursor, wherein the LRE in the diffusion metal can comprise light rare earth including Y, and the HRE can comprise heavy rare earth.

The invention discloses an NdFeB permanent magnet with high coercivity and high resistivity and a method for preparing the same. The method comprises the steps of: spraying powdery slurry containing heavy rare earth compounds, oxides and/or carbides on a flaky NdFeB permanent magnets blank after it is subjected to surface cleaning process; then stacking magnets on top of each other, and performing three-stage heat treatment on the stacked magnets to obtain the NdFeB permanent magnet with high coercivity and high resistivity. Heavy rare earth penetrates into interior of the flaky magnets at a high temperature, so that coercivity of the flaky magnets is improved. However, part of the heavy rare earth elements or alloy elements and carbide powder or oxide powder, which are not penetrated into the flaky magnets, form an interlayer bonding two of flaky magnets together.

The production method for a rare-earth sintered magnet according to the present disclosure comprises: a step for producing a molded article by compression-molding a slurry containing a rare-earth element-containing alloy powder and a dispersion medium using a wet-molding device; and a step for sintering the molded article. When the slurry is being poured into the inside of a space forming a cavity of the wet-molding device, a magnetic field is not applied. By pressing of the slurry, the dispersion medium contained in the slurry starts to be removed from the inside of the space.

The present invention involves a graphene-containing rare earth permanent magnet material and preparation method thereof. The graphene-containing rare earth permanent magnet material, comprising: 20.6 to 23.4 weight percent of neodymium, 6.6 to 7.5 weight percent of praseodymium, 0.95 to 1.20 weight percent of boron, 0.4 to 0.6 weight percent of cobalt, 0.11 to 0.15 weight percent of copper, 2.0 to 2.4 weight percent of lanthanum, 1.7 to 2.1 weight percent of cerium, 1 to 5 weight percent of graphene, a remainder being iron. The graphene-containing rare earth permanent magnet material exhibits excellent temperature resistance, good conductivity and magnet properties even without any heavy rare earth elements like terbium or dysprosium, which dramatically reduces the cost, promotes the efficient utilization of rare earth resources and improves product quality. The preparation method within this invention is simple to realize, easy to control, cost-effective and has high production efficiency and stable product performances.

A production method includes producing a rare-earth magnet precursor (S′) by performing first hot working in which, in two side surfaces of a sintered body, which are parallel to a pressing direction and are opposite to each other, one side surface is brought to a constrained state to suppress deformation, and the other side surface is brought to an unconstrained state to permit deformation; and producing a rare-earth magnet by performing second hot working in which, in two side surfaces (S′1, S′2) of the rare-earth magnet precursor (S′), which are parallel to the pressing direction, a side surface (S′2), which is in the unconstrained state in the first hot working, is brought to the constrained state to suppress deformation, and a side surface (S′1), which is in the constrained state in the first hot working, is brought to the unconstrained state to permit deformation.